Applicare la formula: $a+\frac{b}{c}$$=\frac{b+ac}{c}$, dove $a=-\frac{1}{2}x$, $b=x^2$, $c=2$, $a+b/c=\frac{x^2}{2}-\frac{1}{2}x$ e $b/c=\frac{x^2}{2}$

Applicare la formula: $\frac{a}{b}c$$=\frac{ca}{b}$, dove $a=-1$, $b=2$, $c=2$, $a/b=-\frac{1}{2}$ e $ca/b=2-\frac{1}{2}x$

Applicare la formula: $ab$$=ab$, dove $ab=2\cdot -1$, $a=2$ e $b=-1$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=-2$, $b=2$ e $a/b=-\frac{2}{2}$